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Warning about 12 volt

 

 

 

A word about our LCD TV sets, something you should read very carefully before making your purchase from anywhere else!!!

Sets that have a 12 volt DC input in the back of them really should NOT be connected to a 12 volt battery supply without a regulator.

You can buy one here

 

HISTORY

Some years ago it was rare to find a 12 volt TV set, the only one really available in the UK was a Ferguson 14M2 and this had to have a separate power supply added. Then Samsung came along with their Baby 10 and that set, in its various guises, became the benchmark for the 12 volt TV set market. 10" sets suited most caravans due to their size and the fact that they consumed less power. There were other sets made for the 12 volt market, but these were the main players.

A little later other sets came to be made, again using a 10" tube (the same one) and offered DVD, and VCR and one even came with a hard drive recorder! Some of these sets are still around today. The main voltages on the board inside the sets are probably 48 volts, so when used on the mains you stepped down, and on 12 volts you stepped up, a sort of mini inverter inside the set.

TODAY

With LCD (and their mass production) a number of things changed. The first thing that LCD gave us was lower power consumption; you do not need as much electricity to change the colour of a crystal as you do to light up a tube. This meant that increasingly smaller power supplies could be used. The other thing that has changed is the way the sets are actually made.

Imagine if you will a very large factory in, say, the far east (although a lot of sets are now made in Eastern Europe) making TV sets. The TV system changes all over the world, a set made for the UK will not work in, say, America. The broadcasting systems are different and so are the voltages on the mains. So previously sets had to be made to suit each country. Of course this meant many different production lines and somebody having to either forecast orders and demand, or react to them and thus make them to order, keeping the customer waiting.

The solution to this problem came with a process whereby the sets are MADE in the factory but not actually FINISHED there, or are made as “multi region” but with no mains power supply included. So sets are more or less finished and then put to one side.

When they are sold they are finished either at the factory where they were made or sent to a factory in the country they are sold in to to be finished (this also keeps the weight down). The factory add the correct power supply to suit the TV set and the country, and insert the tuner (if required) for the system operating in the country. They then box them back up and pass them to the purchaser.

THE PROBLEM

In order to make the power supply easy to add the sets are often standardised at 12 volts with a socket on the back to take a 2 or 4 pin plug, meaning that the sets do not have to be dismantled to add the power supply. So suddenly there is a glut of ostensibly 12 volt TV sets out there, or is there? Well the power supplies added at the factory are normally of the switch mode variety and offer a very stable DC supply. 12 volts off your car/boat/caravan battery is anything but stable!!

Firstly when the engine is NOT running the voltage can be anything from 13.8 volts approximately to - well zero! Secondly when the engine is running the voltage with the addition of the power from the alternator can be well over 14 volts, and anything but stable. Now given that the sets need a steady 12 volts (give or take a tiny amount) to operate correctly it is easy to see that something that has 12 v DC written on it is not necessarily happy just to be connected to a car battery with the variances that can offer.

We are aware that some sellers of similar products to ours sell these sets with a DC cord that is just a cigar lighter plug at one end and a plug that goes in the back of the TV set. Fine if the voltage remains fairly constant, but as the voltage gets lower during normal use the sets will draw more current to compensate, meaning the cable connecting the two together could get very hot at best and at worst....well you decide.

How many times have you had flat domestic batteries in your boat or caravan? This is the exact scenario that can damage the set!

THE SOLUTION

All my TV sets come with a REGULATED 12 volt power supply (which will also work on 24 volt) to protect you against voltage drop. This means that when your battery is being charged the output is stable, when the battery is fully charged the output is stable and when you battery is running low the voltage is actually INCREASED by it. At some point if the voltage from the battery gets too low the unit will shut down, and thus shut the TV set down with it to prevent damage to it.

You can buy one here

 

I have been selling low voltage TV sets for years…………………

Sets that have a 12 volt DC input in the back of them really should NOT be connected to a 12 volt battery supply without such a regulator.

You have been warned.

You can buy one here

 

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